Generally, in handling electronic parts or components constituting electronic parts in manufacturing processes for electronic parts, there are ways to handle a plurality of parts together and ways to handle each part separately. When electronic parts are manufactured in the latter way, up to now, a holding jig for holding electronic parts and components thereof, for example, as shown in FIG. 7, has been used in order to handle each of the parts collectively. In FIG. 7, a metal tray 11 is shown and cavities 12 for arranging a plurality of parts are formed by press molding, or the like, in advance. When semiconductor chips, for example, are wire bonded by using such a holding jig, substrates are arranged in the tray 11, the semiconductor chips are die bonded on each of the substrates, and then the chips are wire bonded. However, in these processes, because the substrates are required to be fixed in the tray 11, the upper surface of the tray 11 was covered by a pressure jig 13, where openings 14 in accordance with the arrangement of the substrates, and a pressure leaf spring 15 for fixing each of the substrates, are formed. When the substrates are disposed inside the concave cavities, clearance is required between the cavity and the substrate in consideration of the ease of inserting and removing substrates and dimensional tolerance limits. Therefore, the position of the substrate inside the cavity may vary, and moreover because the substrate is displaced when it is transferred between processes, the coordinate position of the substrate becomes different inside the cavity, depending on the processes. As a result, when each process is automated, errors in positional recognition are likely to occur, and an additional process for correcting the errors is required.
Furthermore, when the substrate is held down by the pressure leaf spring 15 shown in FIG. 7, an extra space for the pressure leaf spring 15 is required at the substrate. Because of this, it is difficult to make the electronic parts small. In particular, if the pressure leaf spring is made too small, it is difficult to securely hold the substrate, and accordingly the smaller the size of the substrate, the higher the ratio of the space occupied by the pressure leaf spring to the size of the substrate, and therefore miniaturization of the substrate is obstructed.
Furthermore, because the above-mentioned cavity is determined by the size of the substrate and the arrangement pattern of a plurality of substrates, an exclusive tray is required for electronic parts of one kind and is not appropriate for broader use. Therefore, the costs, such as the processing cost, material cost, die cost, and the like, for making the tray is substantially increased.
Accordingly, in Japanese Examined Patent Application Publication No. 7-93247, the applicant of the application concerned, applied for a holding jig for small parts and for a holding method therefor which can solve the various above-mentioned problems.
In the above holding jig, an elastic rubber material, at least the surface of which is adhesive, is used, and small parts are made to be held on the surface to which the parts adhere.
According to such a holding jig and holding method, advantages such as the capability of fixing parts in place, the possibility for broad use and miniaturization, for example, are possible.
However, general characteristics of rubber materials are that the volume resistivity is extremely high and insulation characteristics are exhibited. Accordingly, electrostatic charges are likely to be caused in the insertion and withdrawal, transport, and manufacturing processes of electronic parts or their components. Therefore, the following problems may tend to occur.
1) If such a holding jig and holding method are applied to electronic parts having low electrostatic withstand voltages, there is a risk that the electronic parts will be subjected to electrostatic discharge damage during manufacturing.
2) When small, thin, and light electronic parts or components thereof are handled, holding failure is likely to occur because of electrostatic attraction or repulsion due to the above-mentioned electrostatic charges, and there is a risk that the electronic parts will be damaged and lost and that the holding jig will be damaged.
3) Even when such a holding jig and holding method are applied to electronic parts other than those in 1) and 2), there is a possibility of damaging the electronic parts if electrostatic charges are not eliminated prior to use or during use of the holding jig. Therefore, the necessity of providing exclusive equipment for eliminating the electrostatic charges arises.